Chair



July 11, 1933. J. H. KELLOGG CHAIR Filed Jan. 17, 1931 35 fatigue.

Patented July 11, 1933 JOHN HARVEY KELLOGG, OF BATTLE CREEK, MICHIGANCHAIR Application filed January 17,- 1931. Serial No. 509,316.

This invention relates to improvements in chair constructions.

The general contour of the trunk of the body is convex in front andconcave behind. This general form is essential for the normalfunctioning of the lungs, heart, liver, stomach, colon and other organsof the chest and abdomen. The spinal column, which with the ribs formsthe framework and support of the 710 soft parts of the trunk, is astructure so devised that it permits great latitude of temporary changein form while insuring, under normal conditions, maintenance of theessential physiologic curves of the trunk.

In quadrup'cds, the normal curves of the trunk are maintained bygravity; but in human beings, when the body is erect, either in thestanding or sitting position, gravity tends to destroy the normal spinalcurves and 2 to pull the trunk out of shape. The influence of gravity isresisted (a) by ligaments which connect the ribs and vertebrze in such amanner as to maintain the normal or physiologic curves; and (b) by morethan 50 muscles so v placed between the spine andribs, pelvis and headthat by voluntary action they may maintain the normal anterior convexityof the spine. When these muscles are relaxed, however, the trunk becomesmore subject to the action of gravity and may assume postures which arehighly detrimental to health. When the muscles are thus relaxed, anextra strain falls upon the ligaments, especially the costo-vertebralligaments, causing pain an If the occupant of a chair be enabled,assisted and encouraged to maintain the normal trunkal curves whilerelaxed he will derive greater rest and recuperation, both real andapparent, than if he slumps down in a chair, as is commonly done andassumes a posture which is unhealthful for the human body. For example,it is not unusual for a person to so recline in a chair that his spineis permitted to curve 'rearwardly toward the chair back, while hisshoulders are thrown for wardly. Long continued sitting with the lumbarspine unsupported causes backward displacement and fixation of thelumbar vertebraeand a straightening of the spine,- which exposes thecentral nervous system to constant irritation, especially when one isriding on a railroad or in an automobile.

The vertebrae and ribs form a cage for the lungs. The bony parts supplyfixed points for the attachment of muscles by which the chest isexpanded and contracted in the act of breathing. The normal curves ofthe spine give the chest its proper contours and must be maintained toenable the chest to act freely and to expand to its full capacity.Failure to support the flexible portions of the trunk and to maintainthe proper spinal curves results in reducing the size of the chestcavity and relaxing the walls of the abdominal cavity. The circulationof blood and lymph, the

control of which to a large extent centers in the lower abdomen, isseriously disturbed when the trunk of the body is not held up in itsproper shape and the abdominal muscles are relaxed. A surplus of bloodthen accumulates in the abdomen and the rest of the body is inadequatelysupplied.

lVhen the proper trunkal posture is not maintained the liver and otherheavy organs of the abdomen sag down and drag after them the diaphragmto which they are attached. The diaphragm pulls down upon the heart andforces it into a vertical position in which it is under constant strain,and when it beats it, is compelled to lift the liver, stomach and otherorgans which hang suspended from the underside of the diaphragm. Hence,while d the slouching or slumping posture may seem restful, in fact itis itself productive of further fatigue and while it may by contrastwith a standing position appear to be a relief from fatigue it is infact far less adapted to yield relaxation and recuperation than thecorrect posture made possible by this invention.

This invention aims to provide a chair so shaped that the normalanterior convexity of the trunk and the natural curves of the spine aremaintained even when the muscles are completely relaxed, thus preventingabnormal strain upon the ligaments, displacement of the viscera andvarious crippling deformities, such as flat chest or bulging abdomen.This invention not only serves as a preventive of bad posture habits andvarious injuries which result from sitting in the ordinary chair, but isa most effective means of posture training and also of correctingposture defects and deformities.

A special study of postural defects and their causes indicates to methat when the body is in the sitting position, support of the entireback is necessary, and especially is it necessary to support the upperdorsal spine and the shoulders. A point of capital importance is thenecessity for so placing the support for the shoulders and that of theupper spine that the latter shall be appreciably in advance of theformer. This is due to the fact that because of the large muscularmasses on each side of the spine and the shoulder blades overlying them,the upper spine lies at the bottom of a furrow. For

safety and comfort in sitting it is necessary that the back should restagainst a support which conforms to the normal shape of the back whenthe back is in the desired posture known to be conducive to healthfulrelaxation. If the support is flat or hollow, the shoulder blades slipforward, and the spine is by the weight of tee upper part of the trunk,arms and head forced backward, while the chest drops, the abdomen sags,the back is rounded, and all the injuries resulting from bad posturethen result. To prevent this, the center of the upper part of the chairback is extended forward suiiiciently to fill the natural furrow betweenthe shoulder blades. It is also necessary that the remainder of thechair back should be curved so as to follow the'contour of the body andthus support the sides of the trunk, thereby preventing the undueconcentration of pressure upon a small area.

In general, therefore, it is an object of this invention to provide asupport for the back so shaped that it promotes genuine recuperation andis never promotive of deformities or improper posture habits. Otherobjects and advantages of the invention will become apparent upon aperusal of this specification.

In the drawing:

Fig. 1 is a sectional view on the line 11 of Fig. 2 showing a chairconstructed in accordance with this invention.

Fig. 2 is a front elevation of the same chair.

Fig. 3 is a sectional view on the line 33 of Fig. 1.

In the drawing there is shown a chair having .the usual four legs, ofwhich legs 1, 2 and 3 are shown, upon which is secured a seat 4, thesurface of which is shaped to conform to the curves of the human bodyand is generally inclined downwardly toward the rear as shown in Fig. 1to decrease the tendency of the body to slide forwardly thereon.

The chair back comprises the upwardly extending frame members 5 and 6between which is aflixed the chair back frame 7. As shown particularlyin Figs. 1 and 2 the lumbar vertebrae of the spinal column are urgedinto a forwardly convexed normal curvature by means of a horizontallyextending for wardly projecting surface on the chair back upholsteryreferred to throughout its extent by the numerals 8. This portion of thechair back supports what'is commonly known as the small of the back.Above the lumbar supporting portion of the chair back and convexedforwardly from the general surface of the chair back is .what I term thedorsal support 9. Commonly in this portion of a chair back the surfaceis concaved toward the rea 1 rather than convexed toward the front,causing the occupants back to become rounded from shoulder to shoulder,pushing against the shoulder blades, forcing them for,- wardly andflattening the chest, a'posture which is kn own to be decidedly harmful.Thev dorsal support 9 herein provided supportsthe back between theshoulder blades and in the region of the dorsal vertebrae, tendingto-hold these vertebrae in their normal forwardly recessed position inthe human body, encouraging and enabling the shoulders to roll.

back, and allow the chest thus to expand. However, without additionalsupport for the upper part of the trunk there would be a tendency forthe back of the person to rock about the dorsal support 9. ConsequentlyI have arranged that the lateral margins of the upper portion of thechair back, namely at the positions marked 11, be curved forwardly so asto touch against the outer ex-- tremities of the shoulders of theoccupant, supporting them when they are back in their proper position.By this combination of supports the entire back is supported at each andevery portion in a manner most conducive to the proper maintaining ofall of the organs of the body in the positions best suited for theireasy and healthful functioning.

The lower portion of the chair back at 12 is cut back and terminates atthe line 13 thus contributing to the natural posture of the lowerportion of the back of the occupant.

The surface of the seat back is inclined generally from a verticalposition sufficiently so that when the human back is resting snuglyagainst the supporting surfaces the weight of the upper part of thetrunk will naturally be thrown suiiiciently against the lumbar support 8as to maintain the lumbar curve naturally and against the dorsal support9 so as to naturally and without conscious effort cause the chest to benormally expanded and the shoulders to recline comfortably in theconcaved supporting surfaces provided for them. Experimentation hasdetermined that if the upper half of the chair back above the small ofthe back be inclined at about80 from the horizontal the desired effectwill be obtained.

The manner of providing proper relative curvatures of the surface of thechair back is subjectto considerable variation. For example, a number ofpads could be placed upon a flat frame and shaped and combined so as toequal the structure shown in the drawing. On the other hand, the paddingassembled on the rear frame member 7 may be arranged and fixed and thencovered with some suitable upholstery so as to give a unitary appearanceto the entire chair back, retaining however all of the advantages of theinvention.

The chair constructionherein disclosed is found tobe exceptionally wellsuited for use in school rooms and also for use in theaters, althoughitis evident that it should find many other very proper uses.

Having shown and described my invention, I claim:

1. A chair back having a surface forwardly convexed about a horizontallyextending axis to support the lumbar region of a human back in itsnormally curved position, a concave surface below said convexed surface,and above said convexed surface a pair of concave shoulder supportingsurfaces whose lateral margins curve forwardly and whose inner marginsmerge with a centrally located convexed surface provided on the chairback therobetween.

2. A chair back having a surface forwardly convexed about a horizontalaxis in the lower half or the chair back, a surface thereabove forwardlyconvexed about an upward 1y extending axis arranged centrally of thechair back, and concave shoulder supporting surfaces at both sides ofthe second convexed surface, the lateral margins of said shouldersupporting surfaces being curved forwardly.

3. A chair back provided with a centrally positioned surface of gentlecurvature forwardly convexed about an upwardly extending axis arrangedto give support directly to only that portion of the occupants backwhich lies immediately adjacent his dorsal vertebrze, and concaveshoulder supporting surfaces on either side of said central surfacemerging therewith and curved forwardly at their lateral margins.

4. A chair back provided with a centrally positioned surface of gentlecurvature forwardly convexed about an upwardly extending axis arrangedto give support directly to only that portion of the occupants backwhich lies immediately adjacent his dorsal vertebrae, and at both sidesof the first surface concave shoulder supporting surfaces the lateralmargins of which curve forwardly approximately as far as the forwardmostportion of the first said surface.

In witness of the foregoing I aflix my signature.

JQHN HARVEY KELLOGG.

